Rad4life: line of research on orthogonal ray imaging

by Hugo Simões (LIP)

Wednesday 5 Feb 2014, 14:00 → 15:00 UTC

Sala de Conferências no 3º andar (LIP Coimbra / Departamento de Física)

Orthogonal ray imaging is an imaging technique under investigation in the field of radiation therapy. It consists in detecting radiation dispersed in the patient and emitted at right angles in respect to the beam axis.  It is potentially capable of assisting external photon beam radiotherapy by providing images correlated with the effective dose distribution, and by enabling in parallel low-dose morphologic imaging, mainly on-board tumor/patient imaging prior to the onset of the treatment. Monte Carlo simulations are being carried out with the anthropomorphic phantom NCAT adapted to Geant4. Experimental proof-of-principle measurements were collected with a heterogeneous phantom made of acrylic/air and irradiated with a 6-MV clinical linac. The simulated results show a good visual agreement between the planned dose distribution and the orthogonal ray simulated images. For example, the filling of the nasal cavity of the patient may account for a dose reduction of up to 10 %, which may be detected (hence prevented) with an orthogonal ray imaging system. The case of an irradiation of the lung will also be presented.  In conclusion, orthogonal ray imaging is a new imaging concept for assisting external photon beam radiotherapy that shows a good potential for image-guided radiotherapy, adaptive radiotherapy, and low-dose on-board patient imaging.